Much of what drives the plot of William Shakespeare's Othello is Iago's duplicity. We discover at the opening of the play, in a conversation between Iago and Roderigo, that Iago hates Othello and Cassio because Othello gave Cassio the promotion that Iago felt he himself deserved. In conversations with Othello and Cassio, however, Iago pretends to be their friend. Thus the first conflict we have is between Iago's appearance of friendship and reality of hatred.
Next, Iago plots the murder of Cassio, manipulating Roderigo into doing the actual deed. Next, Iago murders Roderigo to ensure his silence. The major conflict between appearance and reality occurs when Iago manages to blame the murder he committed on Bianca, a prostitute who had been having an affair with Cassio.
The major conflicts between appearance and reality in the play are found in the stratagems Iago uses to convince Othello that Desdemona is having an affair with Cassio, especially Iago's hiding the handkerchief in Cassio's room so that it looks as if Desdemona left it there. Although Desdemona appears unfaithful in the eyes of Othello, the reality is that she is loyal, faithful, and in love with him.